Rocket-propelled device



May 17,1949. M. Go'EHMANN nocxE'r-PRoPELLED DEVICE Filed Dec. 27, 1945 N V EN TOR MourtHCJoehmann BY k ATTORNEY Patented May 17, 1949 UNITED, SixersI ROCKET-PROPELLED DEVICE Maurice H. Goehmann, Dearborn,` Mich., assignor, by llnesne assignments, to United States of America Application December 27, 1943, Serial No. 515,653

3v Claims. (Cl. '14R-49') explosive charge and thus add to the fragmenta-- tion of the projectile. There areinstances when the projectile may become lodgedjin the projector or when the propelling charge, 'when ignited, may develop a pressure within the casing which is. so abnormally high as to cause the casing to burst. Such inadvertent bursting, of course, is apt to cause serious injury to those near the projector. It has been proposed to overcome this danger of inadvertent' bursting of the casing by providing a circumferentially weakened zone in the casing, the strength of which is suiilciently lessthan the bursting strength of the casing to permit the casing to break off from the main body of the projectile in the event an abnormal pressure is developed within the casing. The disadvantage in such lan arrangement is that the projectile is of no further use unless or until a new casing is provided. Obviously this would be impractical in the field.

The primary object of the present invention is to provide projectiles of the aforesaid type with a means which will automatically limit the pressure developed in the casing to a predetermined value whereby to prevent bursting of the casing.

Another object is to provide a rocket-propelled device with a, venturi which will automatically adjust itself to limit pressures developed during lring of .the projectile charge to a predetermined value.

With the above and other objects in view, which will be apparent from the following detailed description to those skilled. in the art, the

present invention consists ofcertain features of' mately on line 3-3 of Figure 2; and

Figure 'l is-a fragmentary view of a modified Venturiarrangement.

Referring to the accompanying drawing, the projectile comprises a 'main projectile body IQ having a cavity il for holding the explosive charge I2, and an elongated casing I3 threadedly or otherwise suitably secured to the trailing end of the body i0, The propelling charge represent-- ed by the cylindrical elements it; is supported by a cage i5, also secured to the trailing end of the body lll within the casing i3.

The rearward end i6 of the casing i3 is reduced in diameter and provided with an inturned radial flange il.

The Venturi device is comprised of an outer toroidal element I8 having itsinner surface suitably contoured to provide the outer wall of the Venturi passage i9, and an annular inner element 20 having its outer surface shaped toprovide the inner wall of the Venturi passage. The forward end of the element It is provided with a-coaxial sleeve-like portion 2i which is integrally connected with the inner wall of the element iii by means of radial vanes 22 of streamlined contour.

The inner Venturi element 2U is slidably mounted on a headed rod 23 extending through the sleeve-like portion 2i and is axially urged against the portion 2l by a compression spring 2li which surrounds the rod 23, the spring abutting a split spring Washer 25 carried within a circumferential groove 26 provided in the end of the rod 23.

Prior to the assembly of the casing i3 to the y projectile body IB the assembled Venturi device is slid into the reduced end t@ of the casing it and secured in place in any suitable manner, such as, for example, by silver brazlng indicated at 2l in Figure l.

lt is to be noted that the inner Venturi element 2@ is formed at its forward end with a conical wall 28 of greater angularity than the remainder. whichwall 218 presents a substantial area exposed to the out-rushing gases'. y The modification, shown Ain Figure 4 is similar to that shown in Figure l, similar parts bearing the same numbers. The inner Venturi element 20 in this construction is of cup-shaped design to present a radial wall 2d to the outrushing gases. V

Thev spring 24, in the devices shown, is so calibrated that it will maintain the inner Venturi element 20 in abutting engagement with the sleeve-like lportion 2l ifor all pressures developed within the casing I3 .by the burning propelling 'charge I4 up to anormal pressure. "However, should the developed pressures exceed this prel niermann determined value. due toa faulty or improperly burning propelling charge. the increasednow of gases acting on the surface 28 in the case of the showing in Figure 1 or the surface 2e in the case of the showing in Figure 4 overcomes the resistance of the spring 24, thus increasing the area loi the Venturi passage I9 and thereby effecting a drop in pressure to the normal value. The normal pressure, of course. is predetermined to be a value less than that which would cause bursting of the casing i3.

There is thus provided an arrangement which is automatically effective to relieve the casing of abnormal or excessive .pressure which, in the absence of such arrangement,v would tend to burst the casing and endanger the lives of those who might be in the vicinity oi' the equipment.

Obviously various changes may be made in the construction and detailed arrangement of the parts described Without departing from the spirit and substance of the invention, the scope of which is dened lby the appended claims.

What is claimed is:

1. In a rocket-propelled device having a propelling rocket charge and a casing surrounding said charge, said casing having an open end through which the gases resulting from the burning of the charge exhaust to the atmosphere, concentric outer and inner elements disposed within said open end and being contoured to 4form a Venturi passage therebetween for said gases, said outer element having a coaxial portion and a coaxial rod element carried by said coaxial portion, said inner element being slidable on said rod element, and spring means urging said inner element into engagement with said coaxial portion, said spring means being adapted to maintain said engagement during the development of pressures within said casing up to a predetermined maximum value and to permit said inner element to move axially and enlarge said passage upon the development of pressures above said predetermined value.

2. In a rocket-propelled device having a propelling rocket charge and a casing surrounding said charge, said casing having an open end through which the gases resulting from the burnbeing responsive to an increase in pressurel in ing oi the charge exhaust to the atmosphere, concentric outer and inner elements disposed within said open end and being contoured to'forma Venturi passage therebetween. for said gases; an annular member concentrically disposed within and circumferentially spaced from the inner lsaid casing beyond a predetermined value to slide on said rod against the resistance of said spring to enlarge said Venturi passage.

3. In a rocket-propelled device having a propelling rocket charge and acasing surrounding said charge, said casing having. an open end through which the gases resulting from the burning of the charge exhaust to the atmosphere, a Venturi device within the open end oi' said casing having a Venturi passage of suchrestriction as to permit the propelling charge upon burning thereof to build up pressures within said casing. said Venturi device comprising inner and outer concentric elements, the inner surface of the outer element forming one wall of the Venturi passage and having entrance and outlet ends, said inner element being within the outlet end of the outer element and forming the other wall of said passage, rod means coaxially supported within the. entrance end of said passage an'd extending through and slidably supporting said inner element, and compression spring means carried by said rod4 means and urging said inner element to a predetermined forward position in said passage, said inner element being effective to overcome the resistance of said spring only upon an increase in pressure within said casing beyond a predetermined maximum value.

' MAURICE H. GOEHMANN.

REFERENCES cr'rnn The following references are oi record in the ille of this patent:

UNITED STATES PATENTS Great Britain Mar. 11, 1942 

